Under certain conditions, turbine compressors may experience phenomena related to pressure changes. The phenomena may include a compressor surge or a compressor stall and, occur, for example, when forward flow through a compressor can no longer be maintained due to an increase in pressure across the compressor, which results in a momentary flow reversal.
Traditionally, accelerometers mounted to bearings have been used to detect and count surge events experienced by a turbine compressor. Accelerometers may detect surge events through vibrations of a turbine compressor and are thus able to detect major surge events only, leaving minor surges or stalls unnoticed. This puts a turbine compressor at risk, because surge events, even minor, may cause permanent damage to either or both rotating and stationary blades, sometimes resulting in a catastrophic failure (e.g., rotor blade liberation). Even when it seems that the turbine has avoided catastrophic failure, its air foils may still be damaged resulting in an increased propensity of the turbine to experience successive surge conditions.
Additionally, though the process of surging has been studied, the causes of such events may still be unclear due to the lack of data. Some measurements have been performed for dedicated field testing units only for a very limited amount of time, because measurements and supporting systems used during those tests require an increased amount of supporting infrastructure and external/additional systems on site. The measurements have been collected for gas turbine units that were forced to behave in a certain way at specific arbitrary conditions to simulate the surge effects. However, the measurements were never collected continuously during normal gas turbine operation and integrated into the existing components and control systems.